Sewing machine



Jan. 24, 1928.

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H. JNlsH I SEWING' MACHINE Filed Deo. 14, 1922 5 Sheets-Sheet 5 Wbb Jan. 24, 1928. 1,656,978

H. .JNlsc-a SEWING MACHINE Filed Deo. 14, 1922 5 Sheets-Sheet 4 Jan. 24, 1928.

H. .JNISCH SEWING MACHINE Y Filed Dec. 14, 1922 5 Sheets-Sheet 5 7%/ E7 5262653/ Q/"mann J @Mmmmww Patented Jan. 24, 1928.

UNITED STATESl PATENT OFFICE.

HERMANN JNISQH, OF LIMBACH, GERMANY, ASSIGNOR, :BY MESNE ASSIGNMENTS, T0 i LEWIS INVISIBLE STITCH MACHINE Co., OE ST. LOUIS, MISSOURI,l A CORPORATION F MAINE.

SEWING MACHINE.

Application filed December 14, 1922. Serial No. 606,766.

My invention relates to blind-stitch sewing machines, and has for its general object -to provide a simple, efficient, high-speed blind-stitch machine capable of, and especially adapted for, working upon very thin elastic materials, such as the thin fabrics of silk and of other materials used in gloves vand undergarments, and forming a chain stitch of great elasticity so that stretching of the seamed materials will not break the thread.

More particularly my invention provides, in coordination with a suitable feeding mechanism of a type especially adapted for Such work as above stated, a simple and eflcient stitch-forming mechanism, including a looper mechanism especially adapted to handle the thread in conjunction with cloth feeding mechanism of the character provided.

In the drawings wherein I have illustrated a single embodiment of my invention for purposes of disclosure, but without intent to limit myA invention to the details thereof, Figure l is a front elevation, with parts broken away; Figure 2 is an end elevation with parts broken away; Fig. 3 is a plan view; Fig. 4 is an inverted plan view; Fig.

5 is a plandetail of the stitch forming parts,

as viewed On the section line 5-5 of Fig. 2;

Fig, 6 is a front elevation of said parts with the presser-foot in section'and Fi s. 7 to 11 are diagrams of operation of 51e looper mechanism.

The base houses the main shaft 16 from which all driven parts are operated, this base being surmounted by a hollowl workplatform or table 17 by which the workpresenting and feeding mechanism is carried. Preferably this table is relatively Short, or narrow in the direction of length of the machine, and the work-presenting means may be located close to the inner edge of the table as shown in Fig. 1. For the fine character of work contemplated, the work-preseting and feeding mechanism should vbe such as constantly to presenta bend in the work, for penetration byu the needle, always at the same level, and at this end I preferably employ a narrow feed wheel 18, sharply ridged or double-beveled at its periphery,

mounted on a positively-positioned shaft 19 with its uppermost peripherial sector projecting through an opening 20 in the table.

For feeding purposes the beveled edges of the Wheelmay be toothed or serrated as at 2l, and in operation the wheel may be given .unidirectional step by step rotation for feedlng purposes.

With the specific mechanism for im arting Work-feeding rotation to the whee the 'present invention is not concerned, but one effective operating mechanism for the wheel .1s illustrated as comprising, generally, a

-frictioual feed band 22 embracing a hub 23 of the wheel, this band being split and provided with terminal lugs 24 `and 25. Lug 24 is connected by links 26 and 27 to ya pivot pin 28 on anchoring bracket 29, the vertical link 27 having a lever arm 30 connected to eccentric strap 31 for an eccentric 32 on the main shaft 16. The other lug 25 is perforated to slidingly receive pin 34 of eccentric strap 35 for. an eccentric 36 mounted on a main shaft, and the in 34 has a spring 37 interposed between its head and the lug 25. This provides one Suitablemeans for unidirectional rotation of the feed wheel through a friction clutch that iS alternately tightened and loosened, and is given an oscillating displacement around the wheel-axis 19 by the positive action of the suitably-timed eccentrics, but other suitable feed mechanisms may be substituted, if desired.

As far as the present invention is concerned, it is desirable that the lane of presentation of a sharp band of t e work` be unchanging, and that the bending device be located close to the inner side of Athe work-table, and for simplicity it is desirable to employ the feeding wheel as the bending instrumentality.

The stitch-forming mechanism, arranged' to work wholly fromabove the Work-presenting means, has its actuated arts carried by the overhanging arm 40 projecting from a vertical post 41, the overheadv frame being preferably supplemented by a central bracket 42 to support the needle-bar and a portion -Of the looper. The slender needle 44 is carried by a horizontally-arranged, reciprocat-` ing needle bar 45 and is slidably 'mounted' in the forked lower end ofbracket 42. The needle, in'its reciprocation, travels in guided relation to a 'presser-foot 46 that cooperates with the feed wheel, and is slotted Aas at 47 (Figs 5 and 6) so that the feed wheel may 4 reciprocable present a bend of the work through this presser-foot work-opening. With the needle there cooperates a main looper-member or looper-hook 48 arranged for oscillation in a horizontal' plane, parallel with and slightly above the line of needle travel. And with the main looper element there cooperates a secondary looper element or loop-holder 49, vibratable in a plane substantially at rightangles to the pla-ne of operation of the main looper.

For driving all of these working parts from the main shaft two ecccntri'cs 50 and 51 are provided, the former working the needle bar and the main looper member, and the latter operating the secondary looper member. Eccentric 50 has its strap 52 connected by stem 53 and universal ball-joint 54 with the bell crank arm 55 of a double lever 56, one operating arm of which, indicated at 57, extends down Within the post 41 for connection through link 58 with a bracket 59 on the needle-bar. This operating lever for the needle-bar also carries the takeup finger 60 that projects through a slot 6l in the base of the post.. The other arm, 63 of the double lever 56, extends up and above the frame arm 40, and at its upper end has pivotal connection 64 with a link 65 that imparts motion to the laterally oscillatable main-looper member 48.V

The presser-foot 46 is mounted on vertical presser-bar 67, impelled by spring 68 toward the work-presenting feed wheel, and the bar may be raised against the tension ot its spring by a knee lift lever 69 that acts a ainst a lifter bar 70 arranged in the head o arm so that its pin 71, extending into connection with the presser-bar, may elevate the latter when the knee lift lever is depressed. The presser-bar correspondingly has a pin 72 working between collars 73 on the vertical rock-shaft of the main looper member, so that the latter may be raised and lowered with the presser foot. The narrow foot proper, 46, is angularly 'grooved along its underside, corresponding with the contour of the feed-wheel periphery, and is formed with a grooved needle-guiding projection 74, the groove of which is narrow enough to well steady the needle and finds continuation at 74 (Fig. 5) on that side of the presserfoot from which the needle enters the work. For very tine work of the character particularly contemplated, a very slender needle will be employed, and this extremelyl accurate guidance, in conjunction with the con stantly regulated presentation of the bend of the Work, insures great accuracy in the production of a uniform and blind seam..

The oscillatory looper member 48 is preferably a curved hook having a point t'o engage the needle thread loop, such point terminating at a shoulder 81 which will serve to carry the loop, and such looper hook is arranged to swing in a horizontal plane directly above the needle path through a range of travel substantially as indicated, as to limits, by Figures 7 and 10; that is to say. the point starts from that side ol the needle which is toward the rear of the machine and at a point slightly outward from the scan]- line, and swings across the needle path and forwardly through somewhat more than a quadrant of rotation to bring the shoulder 8l 4finally to a position on the opposite .side et the needle and slightly inward 'l'roin thi` stitch line, or inwardly beyond the crest ot the presser-foot- Thus the main looper hook starting from the position as diagramed in Fig. 7 will take the loo of needle thread as indicated in Fig. 8, an( carry it (during the time that the feed is occurring) over to position indicated in Fig. 9, and in substantially this last position the main looper member should dwell until the vertically vibrating looper member 49 may be moved downward to take, and spread, the needlethread loop and present itl at a low enough elevation to receive the needle on the next penetrating thrust of the latter. For sim licity of coustruction the vertically vibrating or sccondary looper member may be given a direct vibration from a simple eccentric. Such looper member is formed as a generally upright rod or finger 83 having a point 84- terininating at its upper end in a shoulder 85, this looper rod structure bein secured in a vibrating lever arm 8G which 1s pivoted as at 87 to the frame member 42 and which has its opposite end pivotally connected to rod 88 of the eccentric strap 89 which in turn engages the stated eccentric 51. The connections between the vertically disposed rockshatt 90 for the main looper member 48 and the operating link 65 for imparting motion thereto, should be such as to cause a dwell in the operation of the main looper when it is in its forwardmost position shown in Fig. 9, and also it should accommodate the rise and fall of the looper bar commensurate with movement of the presser-foot as heretofore described. In the specific construction shown, therefore, I employ a crank 91 upon the upper end of the looper rod 90 and to its crank beam 92 I pivotally connect one eX- tremit-y of link 93 of a toggle lever, the other link 94 of which, pivotally connected to link 93, `I pivot at its opposite end to bracket- 95 carried by the frame arm 40. To permit the rise and tall of the looper-rod I make one of the toggle links in two pieces pivoted t0- gether on a horizontal axis as at 97, and the pivot pin 98 connecting the two links 93 and 94, I employ as the point of pivot-al connection of the end of link 65.

The effective action of the toggle lever motion for actuating the horizontally swinging main looper member is illustrated in Figs. 7 to 11. The reciprocatory motion of llo link connections 56 and 53 from the eccenltric 50, will betranslated into a diierentialspeed oscillation of the main looper member that will include a dwell of the main looper to permit of easy loop-transference to the Y secondary loop transferer 49, thus as the -main looper will cease.

'link 65 pushes leftward from the position shoyvn in Fig. 6, it will rapidly move the main looper member through its loop-taking excursion, and l continue `the movement ofA the main loo er with decelerating speed untll the togg elinks comernearly to aline of dead-center, when effective motion of the During t-he period of movement of the actuating link from the osition shown in Fig.v 9, to one side of dea -center of the toggle link structure, until the toggle links have been thrown .over dead-center to the position shown in Fig. 10, and brought back a ain to` position indicated in dotted lines in ig. 10, ,the main looper element will substantially stand still, its very slight incidental movement being functionably negligible.'

The two eccentrics 50 and 51 are vso timed that the vertically vibratable secondary looper 49 descends as the needle is startin its forward excursion, and lowers an spreads the loop that has been carried across the seam line by the main looper, so that as illustrated in Fig. 10, it presentsthe loop to be passed through by the needle before the latter penetrates the work, the main looper and secondary looper then successively dis- .engaging themselves from the loop to leave it positioned'upon the needle, subject to the seating of the stitch by means of the take-up member 60, on the subsequent retraction of the needle. l

It will be observed that the accurate positioning of the needleV during the working period of its reciprocation, the constant maintenance of practically uniform conditions in the handling of the athin material between the feed wheel and the presser-foot and the maintenance of a sharp bend in the work at a constant level, are all conductive to ability to handle the thinnest materials and of stretchable nature, ordinarily ditlcult of manipulation in a blind "stitch machine; while the simple and eiective mechanisms for imparting movement to the needlebar andlooper membersare conducive to high speed of operation.J Manifestly the particular character of looper mechanism, sub-divided into two simple parts, each traveling in a single plane of, respectively, horizontal oscillation and vertical vibrat1on,in

coordinates most advantageously with thecharacter of feeding mechanism employed, `that requires a very substantial lowering of the loop from the point wherefthe loop is taken to the point where it is presented to receive the needle, the narrow, sharplyangled-formation of the presser footgiving clearance for the secondary looper operation.

While I have described in some detail a particular embodiment ofimy invention for purposes of full disclosure, it will be apparent to those skilled in the art Y that many changes in details may be made without de yparture from the spirit of my inventionwithin the scope ofthe appended claims.

I claim l. In a blind-stitch' sewing-machine, the

combination of a presser--footjhving a workA aoI presser foot, a needle 'for reciprocation across the presser-foot work opening, and a chain-stitch looper comprising a main looper member oscillatable in a horizontal plane above the needle, and va secondary member vibratable in a plane at right an les` to the first to take the loop from the rst said member and depress and spread it, said.,

prising a reciprocating needle, a'main looper` hook mounted to oscillatejn a /horizontal plane, means for imparting to said main looper member motion at a variable rate to give a dwell at the end of its loop-carrying excursion and including a crank connec with the main looper member, a fixed -bearin stud, a jointed toggle-lever'connecting said crank and stud', and actuating means lconnected to the joint of said toggle lever;

an auxiliary looper member mounted for movement of its active, lower end substantially up and down from osition above to position below the plane o operation of the looper hook, for expansion of the loop chiefly in a vertical direction, and means arranged and adapted to vibrate said secondary looper, depressing it to take the loo during such dwell in the motion of sai primary loo er. 'I

3. Ina blmd-stitchsewing machine, the combination of a frame, a presser footvertically movable therein and having an open-v ing, work-presenting means below saidf presserfoot coacting with said openin v, a needle reciprocable above said presser-Ent, and a looper mechanism compris-ing a main. looper member, operative connections between said main looper member and said presser foot adapting them to be raised together, a crank connected lwith the main looper member, a toggle link structure for operating said crank including a verticallyfiexible link, and means connected with the toggle joint for vibrating the same to oscillate the looper member.

4. In a blind-stitch sewing machine, the combination of a frame having a base and an overhanging arm. a presser foot carried by said arm, coacting, work-handling and feeding mechanism carried by said base, a vibrating needle arranged above said presser foot, looper mechanism carried by said overhanging arm including an oscillatable main Vmember and a vibratable secondary member, av main shaft carried by said base, an eccentric thereon, a lever operated by said eccentric having operative connections With the needle and the main looper member to actuate both thereof, a second eccentric on said shaft, and operative connections between said second eccentric and the secondary looper member.

5. A structure as set forth in claim 4,

wherein the needle-thread take-up is carried by the lever that actuates the needle.

6. In a sewing machine for blind-stitching very thin fabrics, the combination of a narrow presserv foot having an angular groove in its under side and a Work opening, a bender working below said presser foot comprising a narrow, similarly angular member having a fixed position, a slender straight, horizontally-reciprocatinglr needle working above the presser-foot across its work opening, and coactinglr loopcr mechanism comprising a main looper member horizontally oscillatable to take the loop and a secondary looper member vertically vibratable to take the loop from the first said member and depress it and spread it around the path of travel of the needle.

7. A structure as set forth in claim 6 wherein said presser foot is provided with needle guiding recesses on opposite sides of the work opening, substantially as described.

HERMANN JNISCH. 

